 /*******************************************************************************
  * Copyright (c) 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.net;

 import java.util.Vector ;

 /**
  * A string pattern matcher, suppporting * and ? wildcards.
  * Note: code copied from org.eclipse.jdt.internal.core.util.StringMatcher on April 3, 2001
  * (version 0.1 - 010901H18 [rename jbl]).
  */
 public class StringMatcher {
     protected String fPattern;
     protected int fLength; // pattern length
 protected boolean fIgnoreWildCards;
     protected boolean fIgnoreCase;
     protected boolean fHasLeadingStar;
     protected boolean fHasTrailingStar;
     protected String fSegments[]; //the given pattern is split into * separated segments

     /* boundary value beyond which we don't need to search in the text */
     protected int fBound = 0;
     

     protected static final char fSingleWildCard = '\u0000';
     
     public static class Position {
         int start; //inclusive
 int end; //exclusive
 public Position(int start, int end) {
             this.start = start;
             this.end = end;
         }
         public int getStart() {
             return start;
         }
         public int getEnd() {
             return end;
         }
     }
     /**
      * Find the first occurrence of the pattern between <code>start</code)(inclusive)
      * and <code>end</code>(exclusive).
      * @param text the String object to search in
      * @param start the starting index of the search range, inclusive
      * @param end the ending index of the search range, exclusive
      * @return an <code>StringMatcher.Position</code> object that keeps the starting
      * (inclusive) and ending positions (exclusive) of the first occurrence of the
      * pattern in the specified range of the text; return null if not found or subtext
      * is empty (start==end). A pair of zeros is returned if pattern is empty string
      * Note that for pattern like "*abc*" with leading and trailing stars, position of "abc"
      * is returned. For a pattern like"*??*" in text "abcdf", (1,3) is returned
      */

     public StringMatcher.Position find(String text, int start, int end) {
         if (fPattern == null|| text == null)
             throw new IllegalArgumentException ();
             
         int tlen = text.length();
         if (start < 0)
             start = 0;
         if (end > tlen)
             end = tlen;
         if (end < 0 ||start >= end )
             return null;
         if (fLength == 0)
             return new Position(start, start);
         if (fIgnoreWildCards) {
             int x = posIn(text, start, end);
             if (x < 0)
                 return null;
             return new Position(x, x+fLength);
         }

         int segCount = fSegments.length;
         if (segCount == 0)//pattern contains only '*'(s)
 return new Position (start, end);
                     
         int curPos = start;
         int matchStart = -1;
         int i;
         for (i = 0; i < segCount && curPos < end; ++i) {
             String current = fSegments[i];
             int nextMatch = regExpPosIn(text, curPos, end, current);
             if (nextMatch < 0 )
                 return null;
             if(i == 0)
                 matchStart = nextMatch;
             curPos = nextMatch + current.length();
         }
         if (i < segCount)
             return null;
         return new Position(matchStart, curPos);
     }
     /**
      * StringMatcher constructor takes in a String object that is a simple
      * pattern which may contain '*' for 0 and many characters and
      * '?' for exactly one character.
      *
      * Literal '*' and '?' characters must be escaped in the pattern
      * e.g., "\*" means literal "*", etc.
      *
      * Escaping any other character (including the escape character itself),
      * just results in that character in the pattern.
      * e.g., "\a" means "a" and "\\" means "\"
      *
      * If invoking the StringMatcher with string literals in Java, don't forget
      * escape characters are represented by "\\".
      *
      * @param aPattern the pattern to match text with
      * @param ignoreCase if true, case is ignored
      * @param ignoreWildCards if true, wild cards and their escape sequences are ignored
      * (everything is taken literally).
      */
     public StringMatcher(String aPattern, boolean ignoreCase, boolean ignoreWildCards) {
         fIgnoreCase = ignoreCase;
         fIgnoreWildCards = ignoreWildCards;
         fLength = aPattern.length();

         /* convert case */
         if (fIgnoreCase) {
             fPattern = aPattern.toUpperCase();
         } else {
             fPattern = aPattern;
         }
         
         if (fIgnoreWildCards) {
             parseNoWildCards();
         } else {
             parseWildCards();
         }
     }
     /**
      * Given the starting (inclusive) and the ending (exclusive) poisitions in the
      * <code>text</code>, determine if the given substring matches with aPattern
      * @return true if the specified portion of the text matches the pattern
      * @param text a String object that contains the substring to match
      * @param start marks the starting position (inclusive) of the substring
      * @param end marks the ending index (exclusive) of the substring
      */
     public boolean match(String text, int start, int end) {
         if (null == text)
             throw new IllegalArgumentException ();

         if (start > end)
             return false;

         if (fIgnoreWildCards)
             return (end - start == fLength) && fPattern.regionMatches(fIgnoreCase, 0, text, start, fLength);
         int segCount= fSegments.length;
         if (segCount == 0 && (fHasLeadingStar || fHasTrailingStar)) // pattern contains only '*'(s)
 return true;
         if (start == end)
             return fLength == 0;
         if (fLength == 0)
             return start == end;

         int tlen= text.length();
         if (start < 0)
             start= 0;
         if (end > tlen)
             end= tlen;

         int tCurPos= start;
         int bound= end - fBound;
         if ( bound < 0)
             return false;
         int i=0;
         String current= fSegments[i];
         int segLength= current.length();

         /* process first segment */
         if (!fHasLeadingStar){
             if(!regExpRegionMatches(text, start, current, 0, segLength)) {
                 return false;
             }
             ++i;
             tCurPos= tCurPos + segLength;
         }
         if ((fSegments.length == 1) && (!fHasLeadingStar) && (!fHasTrailingStar)) {
             // only one segment to match, no wildcards specified
 return tCurPos == end;
         }
         /* process middle segments */
         while (i < segCount) {
             current= fSegments[i];
             int currentMatch;
             int k= current.indexOf(fSingleWildCard);
             if (k < 0) {
                 currentMatch= textPosIn(text, tCurPos, end, current);
                 if (currentMatch < 0)
                     return false;
             } else {
                 currentMatch= regExpPosIn(text, tCurPos, end, current);
                 if (currentMatch < 0)
                     return false;
             }
             tCurPos= currentMatch + current.length();
             i++;
         }

         /* process final segment */
         if (!fHasTrailingStar && tCurPos != end) {
             int clen= current.length();
             return regExpRegionMatches(text, end - clen, current, 0, clen);
         }
         return i == segCount ;
     }
     /**
      * match the given <code>text</code> with the pattern
      * @return true if matched eitherwise false
      * @param text a String object
      */
     public boolean match(String text) {
         return match(text, 0, text.length());
     }
     /**
      * This method parses the given pattern into segments seperated by wildcard '*' characters.
      * Since wildcards are not being used in this case, the pattern consists of a single segment.
      */
     private void parseNoWildCards() {
         fSegments = new String [1];
         fSegments[0] = fPattern;
         fBound = fLength;
     }
     /**
      * This method parses the given pattern into segments seperated by wildcard '*' characters.
      * @param p a String object that is a simple regular expression with '*' and/or '?'
      */
     private void parseWildCards() {
         if(fPattern.startsWith("*"))//$NON-NLS-1$
 fHasLeadingStar = true;
         if(fPattern.endsWith("*")) {//$NON-NLS-1$
 /* make sure it's not an escaped wildcard */
             if (fLength > 1 && fPattern.charAt(fLength - 2) != '\\') {
                 fHasTrailingStar = true;
             }
         }

         Vector temp = new Vector ();

         int pos = 0;
         StringBuffer buf = new StringBuffer ();
         while (pos < fLength) {
             char c = fPattern.charAt(pos++);
             switch (c) {
                 case '\\':
                     if (pos >= fLength) {
                         buf.append(c);
                     } else {
                         char next = fPattern.charAt(pos++);
                         /* if it's an escape sequence */
                         if (next == '*' || next == '?' || next == '\\') {
                             buf.append(next);
                         } else {
                             /* not an escape sequence, just insert literally */
                             buf.append(c);
                             buf.append(next);
                         }
                     }
                 break;
                 case '*':
                     if (buf.length() > 0) {
                         /* new segment */
                         temp.addElement(buf.toString());
                         fBound += buf.length();
                         buf.setLength(0);
                     }
                 break;
                 case '?':
                     /* append special character representing single match wildcard */
                     buf.append(fSingleWildCard);
                 break;
                 default:
                     buf.append(c);
             }
         }

         /* add last buffer to segment list */
         if (buf.length() > 0) {
             temp.addElement(buf.toString());
             fBound += buf.length();
         }
             
         fSegments = new String [temp.size()];
         temp.copyInto(fSegments);
     }
     /**
      * @param text a string which contains no wildcard
      * @param start the starting index in the text for search, inclusive
      * @param end the stopping point of search, exclusive
      * @return the starting index in the text of the pattern , or -1 if not found
      */
     protected int posIn(String text, int start, int end) {//no wild card in pattern
 int max = end - fLength;
         
         if (!fIgnoreCase) {
             int i = text.indexOf(fPattern, start);
             if (i == -1 || i > max)
                 return -1;
             return i;
         }
         
         for (int i = start; i <= max; ++i) {
             if (text.regionMatches(true, i, fPattern, 0, fLength))
                 return i;
         }
         
         return -1;
     }
     /**
      * @param text a simple regular expression that may only contain '?'(s)
      * @param start the starting index in the text for search, inclusive
      * @param end the stopping point of search, exclusive
      * @param p a simple regular expression that may contains '?'
      * @return the starting index in the text of the pattern , or -1 if not found
      */
     protected int regExpPosIn(String text, int start, int end, String p) {
         int plen = p.length();
         
         int max = end - plen;
         for (int i = start; i <= max; ++i) {
             if (regExpRegionMatches(text, i, p, 0, plen))
                 return i;
         }
         return -1;
     }

     /**
      *
      * @param text the text
      * @param tStart the start
      * @param p the pattern
      * @param pStart the pattern start
      * @param plen the pattern length
      * @return whether the region matches
      */
     protected boolean regExpRegionMatches(String text, int tStart, String p, int pStart, int plen) {
         while (plen-- > 0) {
             char tchar = text.charAt(tStart++);
             char pchar = p.charAt(pStart++);

             /* process wild cards */
             if (!fIgnoreWildCards) {
                 /* skip single wild cards */
                 if (pchar == fSingleWildCard) {
                     continue;
                 }
             }
             if (pchar == tchar)
                 continue;
             if (fIgnoreCase) {
                 char tc = Character.toUpperCase(tchar);
                 if (tc == pchar)
                     continue;
             }
             return false;
         }
         return true;
     }
     /**
      * @param text the string to match
      * @param start the starting index in the text for search, inclusive
      * @param end the stopping point of search, exclusive
      * @param p a string that has no wildcard
      * @return the starting index in the text of the pattern , or -1 if not found
      */
     protected int textPosIn(String text, int start, int end, String p) {
         
         int plen = p.length();
         int max = end - plen;
         
         if (!fIgnoreCase) {
             int i = text.indexOf(p, start);
             if (i == -1 || i > max)
                 return -1;
             return i;
         }
         
         for (int i = start; i <= max; ++i) {
             if (text.regionMatches(true, i, p, 0, plen))
                 return i;
         }
         
         return -1;
     }
 }

